Liquid crystal optical modulating element having particular capacitance between lines and method for driving the same

Abstract

An optical modulating element for time division driving having an electrode structure comprising a plural number of signal electrodes and a plural number of line electrodes arranged so as to confront the signal electrodes to form a matrix, and a liquid crystal arranged between said signal electrodes and line electrodes, wherein the electrostatic capacitance between said plural number of line electrodes is made 1000 PF (picofarad) or lower.

I claim: 
     
       1. An optical modulating element for time division driving comprising an electrode structure having a plural number of signal electrodes and a plural number of line electrodes arranged so as to confront the signal electrodes to form a matrix and a liquid crystal disposed between said signal electrodes and line electrodes, wherein the electrostatic capacitance between said plural number of line electrodes is made 1000 PF (picofarad) or lower, and the intervals between the plural number of line electrodes are maintained at a distance of 20 micrometers to 50 micrometers. 
     
     
       2. An optical modulating element according to claim 1, wherein the plural number of line electrodes have a length of 150 mm or longer in the longer direction. 
     
     
       3. An optical modulating element according to claim 2, wherein the intervals between the plural number of line electrodes are maintained at a distance of 25 μm to 40 μm. 
     
     
       4. An optical modulating element for time division driving comprising an electrode structure having a plural number of signal electrodes and a plural number of line electrodes arranged so as to confront the signal electrodes to form a matrix, a substrate supporting at least the line electrodes, and a liquid crystal disposed between said signal electrodes and line electrodes, wherein the electrostatic capacitance between said plural number of line electrodes is made 1000 PF (picofarad) or lower, and the substrate supporting the plural number of line electrodes has a metal light-shielding mask arranged at least on the areas excluding the areas for shutter openings. 
     
     
       5. An optical modulating element for time division driving according to claim 4, wherein said metal light-shielding mask is formed of a film of a reflective metal. 
     
     
       6. An optical modulating element for time division driving according to claim 5, wherein said reflective metal is chromium, aluminum, or silver. 
     
     
       7. An optical modulating element for time division driving comprising an electrode structure having a plural number of signal electrodes and a plural number of line electrodes arranged so as to confront the signal electrodes to form a matrix and a liquid crystal disposed between said signal electrodes and line electrodes, wherein the electrostatic capacitance between said plural number of line electrodes is made 1000 PF (picofarad) or lower, and light-shielding masks having insulating properties are arranged between said plural number of line electrodes. 
     
     
       8. An optical modulating element for time division driving comprising an electrode structure having a plural number of signal electrodes and a plural number of line electrodes arranged so as to confront the signal electrodes to form a matrix, and a liquid crystal disposed between said signal electrodes and line electrodes, wherein the electrostatic capacitance formed between the signal electrode and the line electrode confronted therewith is made 10 PF (picofarad) or lower and the electrostatic capacitances formed between the plural number of line electrodes and the signal electrodes confronted therewith are made equal or approximately equal. 
     
     
       9. A method for driving an optical modulating element for time division driving comprising an electrode structure having a plural number of signal electrodes and a plural number of line electrodes arranged so as to confront the signal electrodes to form a matrix, and a liquid crystal disposed between said signal electrodes and line electrodes, wherein the electrostatic capacitance formed between the signal electrode and the line electrodes confronted therewith is made 10 PF (picofarad) or lower, the electrostatic capacitances formed between the plural number of line electrodes and the signal electrodes confronted therewith are made equal or approximately equal, and a voltage is applied on the electrode of the line to be addressed among the plural number of line electrodes, which voltage being of the opposite phase to that of the electrodes of other lines. 
     
     
       10. A method for driving an optical modulating element for time division driving according to claim 9, wherein a voltage of the same phase as that to be applied on the line electrode to be addressed is applied on the selected signal electrode among the plural number of signal electrodes. 
     
     
       11. A method for driving an optical modulating element for time division driving according to claim 9, wherein there is the period of time for applying an off signal within the period of time for the addressing.